1. Field of the Invention
The present invention relates generally to supervision and control of one or more railway vehicles and, more particularly, to distributed automatic train supervision and control of one or more railway vehicles on a network of a plurality of sections of track having corresponding wayside controller equipment and carborne train operation equipment.
2. Description of the Related Art
In the related art, the movement of railway vehicles within a railway system has been conventionally controlled from a central office with point-to-point serial communication links to each of a plurality of wayside units within the railway system. FIG. 1 shows a block diagram of a conventional control system 100, wherein a redundant configuration comprising a primary master server (PMS) 110 and a secondary master server (SMS) 112 is linked with one or more operator consoles (OC) 114, 116 through a Local Area Network (LAN) 118, possibly an Ethernet or similar network, to a communications server (CS) 120. A wayside controller unit WCU.sub.1A, WCU.sub.2A, . . . WCU.sub.nA is located at each wayside controller location WCL.sub.1A, WCL.sub.2A, . . . WCL.sub.nA, respectively. Each WCU.sub.1A, WCU.sub.2A, . . . WCU.sub.nA is serial linked through dedicated serial links 119.sub.1, 119.sub.2, . . . 119.sub.n, such as a copper cable having an RS-232 connection over two twisted pair or similar, for instance, to the communication server 120. Each WCU.sub.1A, WCU.sub.2A . . . WCU.sub.nA comprises one or more microprocessor-based control units (CU) 122.sub.1, 122.sub.2 . . . 122.sub.n for non-vital operation logic and Input/Output (I/O), such as a GENISYS.RTM. system, and microprocessor-based control units (CU) 124.sub.1, 124.sub.2 . . . 124.sub.n for vital operation logic and I/O, such as a MICROLOK.RTM. system. The GENISYS.RTM. system and MICROLOK.RTM. system is commonly known to be manufactured by Union Switch & Signal Inc. (US&S.RTM.) of Pittsburgh, Pa., U.S.A.
FIG. 2 shows a typical implementation of the control system 100 of FIG. 1. A central office (CO) location 200 typically has a global services (GS) block 210 and an operator console (OC) block 212. The GS block 210 maintains various commonly known railroad operation functions, including a vehicle regulation (VR) block 214, a centralized traffic control (CTC) block 216, and a train tracking (TTT) block 218. The OC 212 maintains various commonly known interfaces, including a man-machine interface (MMI) 220 and a code system interface (CSI) 222. The GS block 210 and the OC block 212 are linked to communicate with each other through a message switching service (MSS) 224. The CSI 222 is linked with a serial link 228 over a multi-access carrier, such as a LAN (not shown), to a communication server (CS) 230, such as a commonly known terminal server. Typically, the CS 230 is linked to a plurality of wayside controller units WCU.sub.1B, WCU.sub.2B, . . . WCU.sub.nB, which are located at each wayside location WCL.sub.1B, WCL.sub.2B, . . . WCL.sub.nB, respectively, through dedicated serial links 232.sub.1, 232.sub.2, . . . 232.sub.n, such as a copper cable for instance. Typically each WCU.sub.1B, WCU.sub.2B, . . . WCU.sub.nB includes, respectively, a non-vital logic (NVL) unit 234.sub.1, 234.sub.2, . . . 234.sub.n, such as a GENISYS.RTM. 2000 unit manufactured by US&S, and a vital logic (VL) unit 236.sub.1, 236.sub.2, . . . 236.sub.n, such as a MICROLOK.RTM. unit manufactured by US&S. Redundancy is commonly provided by linking a second NVL unit 238.sub.1, 238.sub.2, . . . 238.sub.n and a second VL unit 240.sub.1, 240.sub.2, . . . 240.sub.n to the serial link 232.sub.1, 232.sub.2, . . . 232.sub.n that connects each WCU.sub.1B, WCU.sub.2B, . . . WCU.sub.nB, respectively, to the CS 230. Each of the second NVL units 238.sub.1, 238.sub.2, . . . 238.sub.n may be a GENISYS.RTM. 2000 unit and each of the second VL units 240.sub.1, 240.sub.2, . . . 240.sub.n may be a MICROLOK.RTM. unit.
In FIG. 2, as is known in the art, each redundant NVL unit 234.sub.1, 234.sub.2, . . . 234.sub.n, and 238.sub.1, 238.sub.2, . . . 238.sub.n has non-vital operation logic that controls such commonly known functions as signal clear-ahead, entrance-exit routing, and local control panel logic. Likewise, each redundant VL unit 236.sub.1, 236.sub.2, . . . 236.sub.n and 240.sub.1, 240.sub.2, . . . 240.sub.n has vital operation logic that relates to commonly known train protection and safety systems such as switch indication and control functions. These railroad operations and control functions are typically implemented with commonly known physical relays and/or relay logic emulation on a microprocessor. In the related art, the relay logic must be constructed uniquely for each WCL.sub.1B, WCL.sub.2B, . . . WCL.sub.nB because portions of the relay logic are sensitive to the layout and connectivity of particular track sections that are being controlled by each particular NVL and VL unit at each particular WCL.sub.1B, WCL.sub.2B, . . . WCL.sub.nB. The design and implementation work for each WCL may be somewhat mitigated by using semi-standard logic templates, but these templates cannot represent functions that depend on the local structure of the railroad, such as a commonly known route locking function, for instance.
The communication from the CO 200 to each WCL.sub.1B, WCL.sub.2B, . . . WCL.sub.nB was typically achieved through a serial link protocol for point-to-point communication on a point-to-point carrier, such as an RS-232 connection over two twisted pair or similar, as shown in FIG. 1. Newer installations replace the dedicated serial links 232.sub.1, 232.sub.2, . . . 232.sub.n, known as a point-to-point copper cable bundle, with a router 310 and a multi-access carrier 320, such as a fiber-optic ring for instance, while still maintaining a point-to-point communications protocol over serial links 321.sub.1, 321.sub.2, . . . 321.sub.n, that respectively connect to a WCU.sub.1C, WCU.sub.2C, . . . WCU.sub.nC at a WCL.sub.1C, WCL.sub.2C, . . . WCL.sub.nC, as shown in FIG. 3. Similarly to FIG. 1, each WCU.sub.1C, WCU.sub.2C, . . . WCU.sub.nC comprises one or more microprocessor-based control units (CU) 322.sub.1, 322.sub.2 . . . 322.sub.n for non-vital operation logic and Input/Output (I/O), such as a GENISYS.RTM. system, and microprocessor-based control units (CU) 324.sub.1, 324.sub.2 . . . 324.sub.n for vital operation logic and I/O, such as a MICROLOK.RTM. system.
In FIG. 3 the servers 110, 112 carry out commonly known non-vital operation logic for functions such as signal clear-ahead and entrance-exit routing (thereby duplicating these non-vital functions that are also implemented on non-vital wayside controller units WCU.sub.1C, WCU.sub.2C, . . . WCU.sub.nC located at wayside controller locations WCL.sub.1C, WCL.sub.2C, . . . WCL.sub.nC), along with other functions that are not performed at the WCU.sub.1C, WCU.sub.2C, . . . WCU.sub.nC, such as train tracking and vehicle regulation. Note that duplicated conventional functions, such as signal clear-ahead and entrance-exit routing (not shown), are not implemented using relay logic emulation, but are implemented using generalized software-based functions. Thus, conventional functions such as signal clear-ahead and entrance-exit routing are implemented only once and are applied to a number of locations where the functions are required. Configuration information of the particular WCL from a conventional database (not shown), which information includes how the particular WCL is organized, provides the required information about the location to drive variations in the behavior of the function, such as the switch and signal states needed for an entrance-exit routing, for instance.
A problem with the configurations of FIGS. 1, 2 and 3 is the excessive costs arising from the large amount of logic duplicated on the wayside controller units (WCU) and the CO 200 (especially non-vital operation logic such as train routing), particularly in terms of additional hardware, software and engineering. There are also significant limitations as to the types of operation logic that can be reasonably carried out by the non-vital WCL units, given the amount and type of information that is available to them, and the relay-logic representation that is used to program them. For instance, implementation of train tracking in relay logic is impractical. Additionally, with regard to duplication, the location of the CTC 216 at the GS 210 requires duplication of functionality logic at both the GS 210 and the WCL.sub.1B, WCL.sub.2B, . . . WCL.sub.nB.
In addition, conventional Automatic Train Protection (ATP) systems were implemented with a combination of vital wayside interlocking equipment and vital car-borne equipment. Such equipment communicates to an Automatic Train Operation (ATO) system (not shown) located on the vehicle (not shown) and on the wayside (not shown) through serial links or code lines. Logic for railroad operations and control functions is implemented using physical relays or some microprocessor-based system that simulates relay logic. Examples of such equipment would be a MICROLOK.RTM. system and a MICROTRAX.RTM. system on the wayside and a MICROCAB.RTM. system on the vehicle. Each of these systems are commonly known to be manufactured by Union Switch & Signal Inc. of Pittsburgh, Pa., U.S.A. The ATO system on the wayside is implemented using non-vital wayside equipment. Each wayside ATO system comprised simple non-vital road operation logic, such as typical functions implemented in a US&S.RTM. product named Union Route, for instance, and local control panel interface logic. The US&S.RTM. product named Union Route is described in detail in U.S. Pat. No. 2,567,887, which issued Sep. 11, 1951 in the name of McCann, and which is incorporated herein by reference. Such logic is also implemented using physical relays or some microprocessor-based relay simulation systems such as GENISYS.RTM., but without the vitality requirement. The logic is designed to operate correctly with or without proper communication to the CO 200. Communication to the CO 200 was usually carried out with the serial link 228 or similar code line, as shown in FIG. 2. Automatic Train Operation in the CO 200 comprises computer programs that largely duplicate the functionality of each wayside ATO system, but use procedural computer programs rather than relay logic simulation. In some cases, even the control panel logic is duplicated to drive control panels or model boards. Automatic Train Supervision (ATS) is implemented in the CO 200 using the same or similar computers as ATO. These ATO/ATS/ATP systems are typically fully redundant to ensure graceful and minimal reduction of system performance should portions of the system fail. However, loss of communications with the CO 200 would result in the loss of high-level supervisory functions from ATS, such as automatic routing of trains according to a schedule, known as vehicle regulation. Manual supervisory control from the CO 200 would also be lost in this event.
Consequently, a need exists for distributing to the wayside controller locations those non-global automatic train supervision and control functions that have been previously centralized at the central office CO 200.